University of Twente, Netherlands, reports that scientists from its MESA+ research institute have developed a method for studying individual defects in transistors. A group led by Dr. Floris Zwanenburg have now developed a clever method which, at long last, makes it possible to study individual defects in transistors.
Working in the University of Twente’s NanoLab, the researchers first created chips containing eleven electrodes. These consisted of a group of ten electrodes 35 nm wide and, located perpendicularly above them, a single electrode 80 nm long.
Dr. Zwanenburg compares these electrodes to taps – not for water, but for electrons – which the researchers can turn on and off. The researchers first turn on the long electrode, the ‘stopcock’. At a temperature of −270°C, they then open or close the other ‘taps’. This enables them to locate the ‘leaks’, or – in other words – identify the electrodes beneath which defects are located. It turned out that there were leaks under every single electrode.
In a subsequent step, the researchers were able to neutralize more than eighty percent of the defects by heating the chips to 300°C, in a furnace filled with argon. In some cases, there was only a single defect beneath a given electrode. Having reduced the density of defects in the material, the researchers were then able to study individual defects.
“The behaviour of individual defects is of great importance, as it will improve our understanding of defects in contemporary electronics,” explains Floris Zwanenburg. “Of course, the electronics in question work at room temperature and not at the extremely low temperatures used in our study. Nevertheless, this is an important step for fundamental research and, ultimately, for the further development of modern IC technology.”
The research results were published in Scientific Reports (“Passivation and characterization of charge defects in ambipolar silicon quantum dots”)
